The present invention relates to splicing tapes using water- or alkali-dispersible emulsion polymer systems which are functional as pressure-sensitive adhesives. The splicing tapes of the invention are an ecologically friendly replacement for conventional repulpable splicing tapes.
For a tape construction to be repulpable, the adhesive must, for some markets, be water-dispersible or cold water-soluble and, for such markets, pass Tappi Useful Method 213 (Tappi UM213) "Repulpability of Splice Adhesive Compositions," incorporated herein by reference.
Other markets which utilize hot water or alkali for repulping accept a different standard. A product which passes a Tappi Useful Method 204 (Tappi UM 204), a de-inking and repulping test incorporated herein by reference will also satisfy requirements for elevated temperature alkali repulping.
Commercial water-soluble splicing tape products while they may pass such tests have suffered from (a) poor shelf life; (b) poor humidity and/or heat-aged performance; and (c) a propensity to bleed into the paper facestock (which reduces peel performance). Each of these problems is related to the high water-sensitivity of the adhesive used in the tape products. For these reasons the tape is sold in a sealed plastic bag. Such water-soluble adhesives and tapes are described, for instance, in U.S. Pat. No. 3,441,430 to Peterson; U.S. Pat. No. 3,865,770 to Blake, U.S. Pat. No. 4,052,368 to Larson, U.S. Pat. No. 4,413,080 to Blake, and U.S. Pat. No. 4,569,960 also to Blake, each incorporated herein by reference.
A need exists to provide a splicing tape adhesive and tape construction which are repulpable and not sensitive to changes in relative humidity and where no special precautions are required for storage or use.